Meloidogyne enterolobii is a soil-borne disease that seriously harms crop production in tropical areas, and the agricultural losses caused by it are incalculable every year. For the control of root-knot nematodes, the traditional physical and chemical control methods have some disadvantages, while biological control is environmentally friendly and safe for people and livestock, so it has gradually become a research hotspot. This study used the impregnation method to screen strains with killing activity against the second instar larvae of M. enterolobii. The fermentation conditions and treatment time of the screened highly active strains were optimized. The strains were identified using 16S rRNA sequencing as well as physiological and biochemical methods, and growth promoting characteristics were analyzed. The research results indicated that the nematicidal activity of the fermentation supernatant of BWLY1PSB-1, BWLY2X-4 and BWLY3X-11 were more than 65%. Through morphological, physiological and biochemical characteristics, and molecular biology identification, BWLY1PSB-1, BWLY2X-4 and BWLY3X-11 were identified as Staphylococcus pateuri, Bacillus methylotrophicus and Bacillus sp., respectively; The nematicidal activity of the fermentation supernatant of each strain could reach the maximum after 24 h treatment of nematodes, and the optimal fermentation medium was LB medium, and the nematicidal activity of the supernatant reached relatively high when cultured for five days. The research results on the growth promoting characteristics of thee strains indicated that BWLY1PSB-1 had the ability to produce iron carriers and IAA, while BWLY2X-4 and BWLY3X-11 had the ability to produce proteases, cellulases, iron carriers, and IAA. The preliminary screening of excellent strains that can effectively control plant root-knot nematodes and have rowth promoting characteristics would enrich the microbial resources for the biological control of plant root-knot nematodes.

Calix[4]arene, a class of host compounds, is capable of forming host-guest compounds with guest molecules through hydrogen bonding, electrostatic forces, or van der Waals forces. With the incorporation of sulfur atoms into the molecular structure of calix[4]arene, the cavity size of calix[4]arene would increase. At the same time, sulfur atoms offer strong coordination abilities to trace amounts of variable metallic ions (Mn²⁺, Cu²⁺) presented in natural rubber. The complexes prepared by sulfothiacalix[4]arene salt and metal ions can mitigate catalytic effects of variable metallic ions on the aging reactions of natural rubber, thus improving the thermal oxidative aging performance of natural rubber. Sulfothiacalix[4]arene was synthesized and the protective effect of sulfothiacalix[4]arene on the thermo-oxidative aging behavior of natural rubber was investigated by means of FTIR, DSC, TGA and so on. After the experiment, compared with the samples without the addition of sulfothiacalix[4]arene, it was found that the signals of O-H, C=O and C=C in the FTIR spectra of the samples with the addition group were weakened, the thermo-oxidative aging temperatures on the DSC curve were increased by about 18.87 ℃ and 29.90 ℃, and the epitaxial initial thermal decomposition temperatures in TGA were increased by 11.82 ℃ and 15.03 ℃, respectively. It is concluded that sulfothiacalix[4]arene could be used as a highly effective anti-aging agent in the thermo-oxidative aging of natural rubber.

Coconut meat is the main raw material for coconut products processing, which is mainly obtained by importing dehusked coconut fruits in containers, and the rate of bad fruit is high in the process of transportation and storage. In order to explore the method of rapid differentiation and identification, this study used gas chromatography-ion mobility spectrometry (GC-IMS) combined with principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) to analyze the volatile compounds in coconut meat of unstored normal dehusked fresh coconut fruits (FCM) and deteriorated dehusked coconut fruits under 25 ℃/70%, 35 ℃/80% and 45 ℃/90% (DCM-25, DCM-35 and DCM-45). The results showed that 42 volatile compounds were identified in the four coconut meat, including thirteen alcohols, five acids, eight ketones, ten esters, four aldehydes, two pyrazines and three unknown compounds. The alcohols were the most (including ethanol, butanol and propanol, etc.), followed by acids (including acetic acid and 2-methylpropionic acid, etc.), ketones (including acetone, 3-hydroxy-2-butanone and cyclopentanone, etc.), esters (including butyl caproate, ethyl acetate, butyl butyrate and ethyl butyrate, etc.), aldehydes (including 3-methylbutyraldehyde, pentalaldehyde and heptyl aldehyde, etc.) and pyrazines (2-ethyl-3-methylpyrazine). After deterioration, alcohol, acid and ketone volatile compounds increased. Thirteen characteristic volatile compounds, including 3-methylbutyral, cyclopentanone, 3-methylbutanol monomer, butanol monomer, heptaldehyde, acetone, 2-methylpropanol monomer, 2-heptanone monomer, heptanic acid, butyl butyrate monomer, ethyl acetate, ethanol dimer and 2-ethyl-3-methylpyrazine monomer, were analyzed by OPLS-DA, with variable importance in projection greater than 1. The characteristic volatile compounds in FCM were cyclopentanone and butanol monomer by differential heat map. The characteristic volatile compounds in DCM-25 were 2-heptanone monomer, butyl butyrate monomer, ethyl acetate, ethanol dimer and 2-ethyl-3-methylpyrazine monomer (mainly esters, alcohols and ketones). The characteristic volatile compounds in DCM-35 was heptanoic acid (mainly acids). The characteristic volatile compounds in DCM-45 were 3-methylbutyraldehyde, heptyl aldehyde and acetone (mainly aldehydes and ketones). This study would provide theoretical basis for the screening of deteriorated dehusked coconut fruits.

The pericarp color, browning-related enzyme activity and variations in phenolic compounds during the browning process of litchi pericarp were evaluated to investigate the alterations in ingredients caused by pericarp browning of two litchi varieties (Guiwei and Yuhebao) during storage. The indicators were comprehensively evaluated using correlation analysis and principal component analysis. The results showed that at a storage temperature of 4 ℃, the pericarp of Yuhebao was more likely to brown than that of Guiwei. After being stored for three days, the pericarp of Yuhebao exhibited noticeable browning, but Guiwei only displayed a similar phenomenon after seven days of storage. Over the period of 0-14 days of storage, both Guiwei and Yuhebao showed a decline in the total phenolic, flavonoid and proanthocyanidin levels in the pericarps due to browning. Both Guiwei and Yuhebao pericarps exhibited an increased trend in pH value, with the lower rise rate in pH value of Guiwei pericarp compared with that of Yuhebao. Additionally, the level of polyphenol oxidase (PPO) activity in the pericarps of both litchis exhibited a declining pattern, with a more pronounced decline observed in Yuhebao compared to Guiwei. The peroxidase (POD) enzyme activity in the two litchi pericarps exhibited a little decline, whereas the POD enzyme activity in the Yuhebao pericarp was approximately 1.33 times higher than that of Guiwei. Correlation analysis and principal component analysis revealed that total phenols, flavonoids, PPO and pH value were found to have a significant correlation with the browning color of the two litchi varieties. There was a noticeable correlation between the selected litchi varieties and the browning process, indicating distinct differences in the browning status of the pericarp. The findings of this study could offer fundamental data support for future research on suppressing the browning phenomena of litchi pericarp, extracting and processing phenolic active compounds from litchi pericarp.

The accurate identification of sugarcane stem nodes is of significant value for intelligent seed cutting, planting positioning, optimizing the production management process of sugarcane gardens, and improving yields and economic benefits. However, existing sugarcane stem node detection methods still have shortcomings in terms of performance, model complexity, and real-time performance. In order to effectively solve this problem, this study chose to use the advanced YOLOv8 model to visually detect sugarcane stem nodes in a structured scene. First, a field sugarcane image collection experiment was designed, the collected sugarcane images were manually labeled, and an image training set and a test set were established. Then, the YOLOv8 network was used as the sugarcane stem node detection model to determine the optimal hyperparameter combination and conduct model training. Finally, actual recognition experiments in the field are conducted to verify the effectiveness and efficiency of this method. Experimental results show that the precision, recall, mAP, single-frame inference time and model size of our method on the test set are 0.973, 0.958, 0.974,19.80 ms and 6.30 MB respectively. Compared with the Edgeyolo_S_Coco network and Edgeyolo_Tiny network, the mAP value of the YOLOv8_n network has increased by 1.70% and 1.30% respectively, the single-frame inference time has been reduced by 4.71 ms and 1.50 ms respectively, and the model size has been reduced by 33.70 MB and 17.50 MB respectively. This method has advantages in detection performance and generalization ability, and can effectively meet the requirements for algorithm accuracy and model complexity in outdoor environments, providing solid technical support for sugarcane harvesting and planting in intelligent agricultural production.

This study aims to screen the microbial strains capable of producing β-D-glucosidase from fermented vanilla pods and apply the screened strains to the fermentation process of vanilla with the goal of enhancing vanillin production and improving the quality of vanilla bean. Septenary selective medium was utilized to isolate β-D-glucosidase producing bacteria, identify the homology of each bacterial strain and measure the production of β-D-glucosidase activity of each strain on two strains with higher enzyme production. The phylogenetic tree was constructed. The two strains of bacteria with the highest enzyme production in different combinations were sprayed onto the fermented vanilla pods. The content of vanillin, vanillin glucoside, and volatile components in different treatments of β-D-glucosidase producing bacteria were determined. Nine strains were successfully screened from the vanilla pods originating in Madagascar (M), and twelve strains were isolated from the vanilla pods produced by Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences (S). The fifteen strains were detected as Bacillus. M3 and S7 had higher enzyme activities than other isolates. Vanilla pods treated with M3 obtained the highest vanillin content, which reached to 2.25% and possed the highest aroma components. The maximum decrease in vanillin glucoside content was 80.7% when sprayed with M3 and S7 in a volume ratio of 1:1. There were 34 volatile substances in the fermented pods sprayed with M3, making it the most volatile combination of spraying bacteria. In the present study, we successfully isolated β-D-glucosidase producing bacteria for improving the quality of vanilla pods fermentation.

GRAS is a plant-specific transcription factor, which plays an important regulatory role in plant growth and development, and abiotic stress response. GRAS gene family has not been reported in Hevea brasiliensis. In this study, bioinformatics tools were used to analyze the physicochemical properties, phylogenetic relationships, gene structures, chromosome positions, and cis-acting elements of promoters of GRAS gene family members in H. brasiliensis. The expression patterns of HbGRAS were analyzed by transcriptome data and real-time quantitative PCR (qPCR). A total of 91 GRAS family members were identified from H. brasiliensis genome, named HbGRAS1–HbGRAS91, with molecular weights ranging from 14.07–89.46 kDa. The results of subcellular localization prediction showed that HbGRAS was mainly localized in the nucleus and chloroplast. Those proteins were divided into 14 subfamilies based on phylogenetic analysis. The gene structures and motif compositions within the same subfamily were relatively conserved. The 91 GRAS family members were distributed in 17 chromosomes and two scaffolds except for chromosome 11 in rubber tree. We found that 17 HbGRAS genes were involved in 10 tandem repeat events. Collinearity analysis revealed the segmental duplication regions containing 87 HbGRAS genes, suggested that gene fragment duplication may be the major driver of GRAS gene expansion in H. brasiliensis. Cis-acting element prediction showed that HbGRAS family contained multiple phytohormone and stress-responsive elements. The expression patterns of HbGRAS genes had tissue specificity and were associated with leaf development. The expressions of DELLA genes, a member of the GRAS subfamily, were related to the xylem development and were repressed by gibberellin (GA). Those results provide a reference for functional research on the GRAS genes in rubber trees.

Drought, high salinity and low temperature severely damage plant cells, inhibit plant growth, and significantly reduce crop yields. Ethylene-responsive factors (ERFs) in the AP2/ERF superfamily play a key role in plant growth and development, and in stress responses. To investigate the role of MeERF127 in the response of cassava to abiotic stress, this study cloned the MeERF127 gene from cassava and conducted sequence alignment, subcellular localization, transcriptional activity analysis, and expression pattern analysis. A gene-edited vector for MeERF127 was constructed to obtain transgenic cassava, and the phenotype and physiological indicators after drought, salt and cold stress treatments were analyzed, along with the expression of stress-responsive genes. The results showed that the full-length CDS region of the MeERF127 gene was 711 bp, and the amino acid sequence contained YRG and RAYD elements at the N- and C-termini, respectively, with alanine and aspartic acid at positions 14 and 19, indicating that MeERF127 belonging to the ERF subfamily. MeERF127 was localized in the nucleus and had transcription factor activity. MeERF127 was most highly expressed in stems, with the lowest expression in callus tissues, and its expression peaks during the tuber formation stage (80 days after planting). Its expression level increased after drought and salt stress and slightly decreased after cold stress. A gene-edited vector was constructed, and Agrobacterium-mediated transformation of cassava callus tissues resulted in MeERF127 gene-edited lines with 22 and 3 base pair deletions, as confirmed by Hi-TOM high-throughput sequencing. After drought and salt stress treatments, the gene-edited cassava did not wilt, while the wild-type cassava showed significant wilting. The gene-edited cassava had significantly higher SOD and POD enzyme activities and Pro content, and significantly lower MDA content compared to the wild-type cassava. The leaf color of the gene-edited cassava was lighter, and the expression levels of stress-responsive genes SOD and WRKY31 were significantly higher in the gene-edited cassava than those in the wild-type. After cold stress, both gene-edited and wild-type cassava wilted, with no significant differences in SOD and POD enzyme activities, MDA content, leaf color and stress-responsive gene expression between the gene-edited and wild-type cassava. These results suggest that the gene-edited MeERF127 enhances the drought and salt tolerance of cassava but does not respond to cold stress, indicating that MeERF127 may regulate the SOD and WRKY31 genes to respond to drought and salt stress. The findings of this study would provide insights into the role of the MeERF127 gene in cassava's response to drought and salt stress.

SWEET (sugars will eventually be exported transporter) plays an important role in pant flowering. However, the mechanism of flower was unclear in pineapple. In this study, the interacting proteins of AcSWEET11 were identified, in order to lay a foundation for analysis of the flowering mechanism of pineapple. In this study, the interacting proteins of AcSWEET11 were screened from the pineapple flowering cDNA membrane library by co-transformed, and then the expression levels of the candidate proteins during flowering were analyzed. pBT3-STE-AcSWEET11+pPR3-N was nontoxicity for NMY51 yeast cells but had autonomous activation. Further study showed that autonomous activation was restrained after adding 3ʹAT in TDO and QDO. A total of 81 positive clones were screened by yeast two-hybrid, and 48 proteins were identified by sequencing which were probably interactive with AcSWEET11. The proteins were contained E3 ubiquitin-protein ligase RING1-like, Trehalose-phosphate synthase 7, Cytochrome P450 90A1-like and Transcription factor LUX. GO and KEGG revealed that 48 proteins may participate in lipid metabolism, amino acid metabolism, carbohydrate metabolism, signal transduction and transport and catabolism. And the expression of Trehalose-phosphate synthase 7 (XP_020105459.1), Protein TIFY 3-like (XP_020082835.1), 40S ribosomal protein S27 (XP_020092770.1) and Heterogeneous nuclear ribonucleoprotein 1-like (XP_020112516.1) were down regulated during flowering induction that consistent with AcSWEET1 while the expression of Dihydrolipoyl dehydrogenase 2 (XP_020113798.1), Putative lipid-transfer protein DIR1 (XP_020086640.1), Clathrin assembly protein At4g32285 (XP_020108161.1) were up regulated. AcSWEET11 might interact with the proteins such as Trehalose-phosphate synthase 7 to participate in pineapple flowering. The protein interaction network of AcSWEET11 was plentiful to provide a foundation for analysis the regulatory mechanism of AcSWEET11 in pineapple flowering.

Mutation breeding is one of the most promising approaches for increasing genetic and phenotypic variability in a short period of time. In order to explore the feasibility of creating a mango mutant gene library through mutagenesis. The study used Keitt mango as test materials, irradiated branches with ⁶⁰Co-γ ray and soaked seeds in EMS solution to create a mutagenesis population, and analyzed the Genetic diversity by SC-SSR molecular markers. The results indicated that the seemi-lethal dose of ⁶⁰Co-γ ray radiation is 31.37 Gy, and the semi-lethal time of immersion in 0.2% EMS solution is 5.9 hours. The genetic diversity of 100 mutagenized materials and Keitt material was analyzed through 16 pairs of SC-SSR primers, and a total of 117 polymorphic sites were detected. The average values of sexual locus, primer percentage of polymorphism bands, polymorphism information content (PIC), number of observed alleles (N_a), number of effective alleles (N_e), Nei's gene diversity index (H) and Shannon's information index (I) were 93.18%, 0.610, 1.923,1.583,0.334 and 0.493, respectively. The genetic similarity coefficient among test materials ranged from 0.373 to 0.984, with an average of 0.779. The study indicated that mutagenesis significantly enhanced genetic diversity in mango, among which EMS mutagenesis seed variation was greater, and the results lay a solid theoretical foundation for mango mutation breeding.